I have stood on both sides of the table and taught E&E at basic flying training. As RAFG Aircrew I did Bad K and got caught by German Alpine troops who were very well prepared for the 'exercise'. I subsequently did the CSRO Course and all that it entailed. To teach the subject with integrity; I worked with the 'enemy' frequently over a three year period. So you could say I have been there, seen it, etc.
Much is not for discussion with anonymous ears on a public forum. Amongst many reasons why is that things may have changed, and my information is now 22 years down the road. On the assumption that points of administration have not changed; I can tell you that all the bad guys know in advance of a prisoner being presented is how many prisoners there are, and the number written on a tag attached to their clothing. Thereafter everything they learn is an own goal. Air Force/Army/Navy lists where the traditional source of information, especially the Army list that included nicknames or known as names, that permitted a personal interaction. The advent of Facebook and LinkedIn were a Godsend for Interrogators, and if you Google 'London Gazette' and your service number, you may be surprised what you find.
The Israeli R2I doctrine was to speak freely and place the deduction of 'truth' with the interrogator. The US embraced a policy of limited release over a set timeline. The disadvantage of the British stiff upper lip is that a UK prisoner talking is almost certainly telling the truth. Gulf War I showed that Tornado wreckage with ejection seats adorned with RAF station names, and two walking aviators didn't actually have to say too much to work out who they were. This issue was prevelent throughout the Cold War.
Ever wondered why the junior rank of RAF Aircrew is a Sgt? Read the Geneve Convention for there lies the answer. Do contemporary enemies abide by said convention? The Jordanian F16 pilot burned alive answered that one.